IE8 Beta 2 also consumes 52% more memory than IE7 and uses almost three times as many threads, said Craig Barth, chief technology officer at Devil Mountain Software Inc., a Florida-based maker of PC performance testing software.

"IE8 is epically porcine," said Barth. "Microsoft has gone to epic levels of bloat."

Barth tested IE8 Beta 2, IE7 and Firefox 3.0.1 in a 10-site scenario that involved media-rich domains such as boston.com, channel9.com, cnet.com, infoworld.com, nytimes.com and others. Each site was opened by each browser in a separate tab, then links on those sites were opened in new tabs. Both Flash and Microsoft's Silverlight were installed as plug-ins for each browser.

By the end of the test, IE8 Beta 2 had grabbed 380MB of memory on the 2GB-equipped system running Windows Vista, while IE7 consumed 250GB and Firefox 3.0.1, the most-recent version of the open-source browser, had taken 159MB. When the same tests were run under Windows XP, each browser consumed slightly less memory than it did with Vista; IE8 Beta 2, however, continued to lead the competition by wide margins.

"When Windows XP starts, the entire OS takes 130 to 150MB," said Barth. "Suddenly you're looking at a memory footprint for IE that's bigger than Microsoft's earlier operating system. IE8 is fatter than XP."

When Barth tallied up the separate processor threads each browser spawned during the tests, he also found that IE8 Beta 2's count was dramatically higher than either IE7's or Firefox's. The latter, for instance, never used more than 29 concurrent processor threads during the 10-site test, while IE7 spawned a maximum of 65. IE8 Beta 2, however, used a whopping 171 threads.

Piling on the threads, said Barth, "becomes overwhelming after a while," and it can have a direct impact on the speed of the browser. The more concurrent threads, the more operating system overhead managing those threads, and the more the processor is stressed. Web browsers typically use multiple processor threads, but when the thread count climbs, performance can suffer unless the application is running on a multiple-core processor.

That may be Microsoft's plan, Barth speculated. "If a multithreaded application is designed well and runs on a heavily parallel system, like a multicore machine with four or eight [processor] cores, you can get additional performance. My guess is that Microsoft is targeting IE8 at the next generation of hardware."